/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* Debug and Error wrapper functions for dump().
 */
function ERR(response, responseCode, responseCodeStr, msg) {
  // Reset state var.
  setState("expectedRequestType", "");
  // Dump to console log and send to client in response.
  dump("SERVER ERROR: " + msg + "\n");
  response.write("HTTP/1.1 " + responseCode + " " + responseCodeStr + "\r\n");
  response.write("Content-Type: text/html; charset=UTF-8\r\n");
  response.write("Content-Length: " + msg.length + "\r\n");
  response.write("\r\n");
  response.write(msg);
}

function DBG(msg) {
  // Dump to console only.
  dump("SERVER DEBUG: " + msg + "\n");
}

/* Delivers content in parts to test partially cached content: requires two
 * requests for the same resource.
 *
 * First call will respond with partial content, but a 200 header and
 * Content-Length equal to the full content length. No Range or If-Range
 * headers are allowed in the request.
 *
 * Second call will require Range and If-Range in the request headers, and
 * will respond with the range requested.
 */
function handleRequest(request, response) {
  DBG("Trying to seize power");
  response.seizePower();

  DBG("About to check state vars");
  // Get state var to determine if this is the first or second request.
  var expectedRequestType;
  var lastModified;
  if (getState("expectedRequestType") === "") {
    DBG("First call: Should be requesting full content.");
    expectedRequestType = "fullRequest";
    // Set state var for second request.
    setState("expectedRequestType", "partialRequest");
    // Create lastModified variable for responses.
    lastModified = new Date().toUTCString();
    setState("lastModified", lastModified);
  } else if (getState("expectedRequestType") === "partialRequest") {
    DBG("Second call: Should be requesting undelivered content.");
    expectedRequestType = "partialRequest";
    // Reset state var for first request.
    setState("expectedRequestType", "");
    // Get last modified date and reset state var.
    lastModified = getState("lastModified");
  } else {
    ERR(
      response,
      500,
      "Internal Server Error",
      'Invalid expectedRequestType "' +
        expectedRequestType +
        '"in ' +
        "server state db."
    );
    return;
  }

  // Look for Range and If-Range
  var range = request.hasHeader("Range") ? request.getHeader("Range") : "";
  var ifRange = request.hasHeader("If-Range")
    ? request.getHeader("If-Range")
    : "";

  if (expectedRequestType === "fullRequest") {
    // Should not have Range or If-Range in first request.
    if (range && range.length) {
      ERR(
        response,
        400,
        "Bad Request",
        'Should not receive "Range: ' + range + '" for first, full request.'
      );
      return;
    }
    if (ifRange && ifRange.length) {
      ERR(
        response,
        400,
        "Bad Request",
        'Should not receive "Range: ' + range + '" for first, full request.'
      );
      return;
    }
  } else if (expectedRequestType === "partialRequest") {
    // Range AND If-Range should both be present in second request.
    if (!range) {
      ERR(
        response,
        400,
        "Bad Request",
        'Should receive "Range: " for second, partial request.'
      );
      return;
    }
    if (!ifRange) {
      ERR(
        response,
        400,
        "Bad Request",
        'Should receive "If-Range: " for second, partial request.'
      );
      return;
    }
  } else {
    // Somewhat redundant, but a check for errors in this test code.
    ERR(
      response,
      500,
      "Internal Server Error",
      'expectedRequestType not set correctly: "' + expectedRequestType + '"'
    );
    return;
  }

  // Prepare content in two parts for responses.
  var partialContent =
    '<html><head></head><body><p id="firstResponse">First response</p>';
  var remainderContent =
    '<p id="secondResponse">Second response</p></body></html>';
  var totalLength = partialContent.length + remainderContent.length;

  DBG("totalLength: " + totalLength);

  // Prepare common headers for the two responses.
  let date = new Date();
  DBG("Date: " + date.toUTCString() + ", Last-Modified: " + lastModified);
  var commonHeaders =
    "Date: " +
    date.toUTCString() +
    "\r\n" +
    "Last-Modified: " +
    lastModified +
    "\r\n" +
    "Content-Type: text/html; charset=UTF-8\r\n" +
    "ETag: abcd0123\r\n" +
    "Accept-Ranges: bytes\r\n";

  // Prepare specific headers and content for first and second responses.
  if (expectedRequestType === "fullRequest") {
    DBG("First response: Sending partial content with a full header");
    response.write("HTTP/1.1 200 OK\r\n");
    response.write(commonHeaders);
    // Set Content-Length to full length of resource.
    response.write("Content-Length: " + totalLength + "\r\n");
    response.write("\r\n");
    response.write(partialContent);
  } else if (expectedRequestType === "partialRequest") {
    DBG("Second response: Sending remaining content with a range header");
    response.write("HTTP/1.1 206 Partial Content\r\n");
    response.write(commonHeaders);
    // Set Content-Length to length of bytes transmitted.
    response.write("Content-Length: " + remainderContent.length + "\r\n");
    response.write(
      "Content-Range: bytes " +
        partialContent.length +
        "-" +
        (totalLength - 1) +
        "/" +
        totalLength +
        "\r\n"
    );
    response.write("\r\n");
    response.write(remainderContent);
  } else {
    // Somewhat redundant, but a check for errors in this test code.
    ERR(
      response,
      500,
      "Internal Server Error",
      "Something very bad happened here: expectedRequestType is invalid " +
        'towards the end of handleRequest! - "' +
        expectedRequestType +
        '"'
    );
    return;
  }

  response.finish();
}
